The present invention relates to a tool for a food processing machine, comprising:                a tubular casing,        a shaft for rotatingly driving a food processing element, and        a centering and guiding element which ensures that the drive shaft is mounted for rotation in the tubular casing,        the tubular casing and the drive shaft being provided, at the same first end, with removable means for locking to a machine body and releasable means for coupling to a main shaft of the machine, respectively,        the centering and guiding element comprising removable means for fixing to the tubular casing in order to allow the drive shaft to be disassembled from the tubular casing.        
A tool of this type has, for example, been described in the French Patent Application in the name of the same Applicant, published under the number 2 780 264.
The tool described in this previous application comprises a removable roller bearing which is fixed in the tubular casing at the side of that end of the drive shaft on which the food processing element is mounted, that is to say, at the opposite side to the end which is coupled to the main shaft.
It has been found that, depending on the type of removable locking means provided on this bearing, the bearing and therefore the drive shaft could inadvertently become disassembled when the tool was operated.
Inadvertent disassembly of this type can result from the bearing not being completely mounted beforehand in the tubular casing and/or from the locking means of the bearing being retained in an excessively weak manner relative to the mechanical forces applied to the bearing (weight of the drive shaft, centrifugal forces, vibration phenomena etc . . . ).